Questions Raised About Effectiveness of Opioids for Long-Term Chronic Pain

Bethesda, MD—The use of opioid drugs have more than tripled in the past 20 years, with more than 200 million prescriptions written annually in recent years, yet little evidence exists for their effectiveness in the treatment for long-term chronic pain, according to a new National Institutes of Health (NIH) review.

The paper, essentially the final report of a seven-member panel convened by the NIH last fall, finds that many of the studies used to justify the prescription of these drugs were either poorly conducted or of an insufficient duration.

The members of the panel were experienced clinicians with expertise in a variety of areas. “The NIH intentionally invited people from other fields of medicine,”
explained panel member David Steffens, MD, MHS, chair of the psychiatry department at the University of Connecticut Health Center, “in order to avoid potential conflicts of interest, and to get a fresh perspective on the issue.”

Over 2 days, the panel listened to evidence drawn from all available studies on the use of opioid drugs. With the draft report made available for public comment late last fall, the
final report was published recently in the Annals of Internal Medicine.

Based on the information, the widespread use of the drugs is somewhat surprising, Steffens suggests, because “there's no research-based evidence that these medicines are helpful.”

“Clinicians have little evidence to guide them once they make the decision to prescribe opioids for chronic pain therapy. Data on selecting specific agents on the basis of drug characteristics, dosing strategies, and titration or tapering of doses are insufficient to guide current clinical practice,” according to the report.

During the presentations, data were presented on three distinct pain mechanisms:

• Peripheral nociceptive caused by tissue damage or inflammation;
• Peripheral neuropathic caused by damage or dysfunction of peripheral nerves; and
• Centralized, characterized by a disturbance in the processing of pain by the brain and spinal cord.

“Persons with more peripheral nociceptive pain (such as acute pain due to injury, rheumatoid arthritis, or cancer pain) may respond better to opioid analgesics,” according to the report. “Those with central pain syndromes (for example, fibromyalgia, the irritable bowel syndrome, temporal-mandibular joint disease, and tension headache) respond better to centrally acting neuroactive compounds (such as certain antidepressant medications and anticonvulsants) than to opioids.

A workshop speaker noted that evidence suggests nonopioid interventions may better treat fibromyalgia and that patients with even a few signs of the disorder are at risk for poor response to opioids and a worse long-term course of pain, according to the article. Other speakers presented evidence that nearly all chronic pain could have a centralized component, suggesting that opioids might promote progression from acute nociceptive pain to chronic centralized pain.

Several speakers and audience members cautioned, however, about going too far in advocating against widespread opioid use.

The report notes, “Patients, providers, and advocates all agree that opioids are an effective treatment method for chronic pain for a subset of patients and that limiting, disrupting, or denying access to opioids for these patients can be harmful. These patients can be safely monitored by using a structured approach that includes optimization of opioid therapy, management of adverse effects, and follow-up visits at regular intervals.”

Steffens points out that the United States, with just 4.6% of the world’s population, consumes 80% of the world's opioid drugs, making this “a peculiarly American problem.”

“I wish that doctors treating people for sports or workplace injuries would be cautious with the amount of pills they dispense,” he added.